[The morbidities of extremely preterm and extremely low birth weight infants during hospitalization]

Extremely preterm (EP) and extremely low birth weight infants (ELBWI) tended to suffer from some serious complications. How to treat and make them survive reflect the progress of perinatal medicine and neonatal treatment technology. But in our country, there was still lack of data analysis about the morbidities and interventions of large sample survey on such infants. This study was designed to survey the in-hospital morbidities of EP and ELBWI who had been admitted to neonatology departments.

Clinical data of EP (gestational age < 28 weeks) and ELBWI (birth weight < 1 000 g), who were discharged from January 1, 2008 to December 31, 2012, were collected retrospectively from twenty tertiary neonatology departments in Guangdong province. The rates of major in-hospital morbidities such as neonatal asphyxia, neonatal respiratory distress syndrome (NRDS), bronchopulmonary dysplasia (BPD, oxygen therapy at postnatal 28d), hospital-acquired infection (HAI), periventricular-intraventricular hemorrhages (PVH-IVH), periventricular leukomalacia (PVL), retinopathy of prematurity (ROP) and necrotizing enterocolitis (NEC) etc. were summarized and calculated respectively. Comparisons were made among subgroups according to areas of hospitalization, and infants of small for gestational age (SGA) and appropriate for gestational age (AGA). Categorical data were analyzed using the chi-square test, and P < 0.05 were considered statistically significant.

Totally 888 cases were enrolled in the study, including 498 EP and 683 ELBWIs (while 293 cases were both EP and ELBWIs). The mean gestational ages were (27.6±1.7) weeks (22(+6)-35 weeks), and mean birth weights were (928±154) g (300-1 480 g); 57.7% (512/888) of them were male while 42.3% (376/888) were female. The major in-hospital morbidity rates of EP were NRDS 80.3% (400/498), BPD 54.6% (113/207), PVH-IVH 40.8% (111/272), ROP 40.7% (92/226), HAI 28.1% (99/352), Apgar score ≤7 at five minutes 19.6% (87/445), PVL 14.7% (40/272) and NEC 9.4% (37/393), while ELBWI were NRDS 75.5% (516/683), BPD 50.2% (153/305), ROP 31.6% (103/326), HAI 30.3% (149/491), PVH-IVH 29.6% (111/375), PVL 21.9% (82/375), Apgar score ≤7 at five minutes 20.3% (125/617) and NEC 12.2% (66/542). There were 69.2% (614/888) and 79.7% (708/888) of all infants received pulmonary surfactant therapy and ventilator therapy respectively. Infants stayed in the hospitals in Guangzhou and Shenzhen had higher morbidity rates in NRDS (80.6% (382/474) vs. 72.9% (302/414), χ(2)=7.297, P=0.007), BPD (57.7% (146/253) vs. 28.2%(48/170), χ(2)=35.571, P <0.01), ROP (40.9% (114/272) vs. 14.1%(29/205), χ(2)=42.931, P <0.01) and PVH-IVH (34.8% (110/316) vs. 19.5% (48/246), χ(2)=16.017, P <0.01), but had lower rate in PVL (10.1% (32/316) vs. 25.2% (62/246), χ(2)=22.537, P <0.01) than those from other cities. The SGA infants had lower morbidity rates in NRDS (62.9% (149/237) vs. 82.7% (512/619), χ(2)=38.368, P <0.01), ROP (21.7% (25/115) vs. 33.0% (115/349), χ(2)=5.161, P =0.023) and PVH-IVH (13.8% (21/152) vs. 33.3% (132/396), χ(2)=20.791, P <0.01) than AGA infants.

The in-hospital morbidity rates of EP and ELBWI were really high, and NRDS had the highest rate of all. The morbidities could be influenced by many factors which should be managed comprehensively.